Web Service Semantics - WSDL- S · 3 Adding semantics to WSDL – guiding principles •Build on existing Web Services standards •Mechanism independent of the semantic representation

Web Service Semantics - WSDL-S

Meenakshi Nagarajan

for theWSDL-S team

R. Akkiraju*, J. Farrell*, J.Miller, M. Nagarajan, M. Schmidt*, A. Sheth, K. Verma"Web Service Semantics - WSDL-S"

A joint UGA-IBM* Technical Note, version 1.0, April 18, 2005.http://lsdis.cs.uga.edu/projects/METEOR-S/WSDL-S

http://www.alphaworks.ibm.com/g/g.nsf/img/semanticsdocs/$file/wssemantic_annotation.pdf

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WSDL-S

<Operation>

<Input1>

<Output1>

Service Template

Operation:buyTicket

Input1:TravelDetails

Output1:Confirmation

Annotations

Publish

SearchSemantic UDDIOperation:

cancel Ticket

Input1:TravelDetails

Output1:Confirmation

WSDL-S : scope, proposal and thebigger picture

Sivashanmugam, K., Verma, K., Sheth, A., Miller, J., Adding Semantics to Web Services Standards, ICWS 2003

<Operation>

<Output1>

Web service 1

<Input1>

<Operation>

<Output2>

Web service 2

<Input2>

Composition

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Adding semantics to WSDL – guidingprinciples• Build on existing Web Services standards

• Mechanism independent of the semanticrepresentation language

• Mechanism should allow the association ofmultiple annotations written in differentsemantic representation languages

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Guiding principles...

• Support semantic annotation of WebServices whose data types are describedin XML schema

• Provide support for rich mappingmechanisms between Web Service schematypes and ontologies

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WSDL-S• Offer an evolutionary and compatible upgrade of

existing Web services standards

• Externalize the semantic domain models– agnostic to ontology representation languages.– reuse of existing domain models– allows annotation using multiple ontologies (same or

different domain)

• updating tools around WSDL is relatively easier

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Semantic annotations on WSDLelements• Annotating message types (XSD complex types and

elements)– extension attribute : modelReference

(semantic association)– extension attribute : schemaMapping

(schema/data mapping)

• Annotating operations– extension elements : precondition and effect

(child elements of the operation element)– extension attribute : category

(on the interface element)– extension element : action

(on operation element)

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…………<xs:element name= "processPurchaseOrderResponse" type="xs:stringwssem:modelReference="POOntology#OrderConfirmation"/></xs:schema></types><interface name="PurchaseOrder"><wssem:category name= “Electronics” taxonomyURI=http://www.naics.com/

taxonomyCode=”443112” />

<operation name="processPurchaseOrder” pattern=wsdl:in-outaction = "rosetta:#RequestQuote" >

<input messageLabel = ”processPurchaseOrderRequest"element="tns:processPurchaseOrderRequest"/><output messageLabel ="processPurchaseOrderResponse"element="processPurchaseOrderResponse"/>

<!—Precondition and effect are added as extensible elements on an operation><wssem:precondition name="ExistingAcctPrecond"wssem:modelReference="POOntology#AccountExists"><wssem:effect name="ItemReservedEffect"wssem:modelReference="POOntology#ItemReserved"/></operation></interface>

PurchaseOrder.wsdls

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Annotating operations• extension element : Precondition

– A set of assertions that must be satisfied before a Web service operation can beinvoked

• “must have an existing account with this company”• “only US customers can be served”

• extension element : Effect– Defines the state of the world/information model after invoking an operation.

• “item shipped to mailing address”• “the credit card account will be debited”

• extension attribute : Category– Models a service category on a WSDL interface element.

• category = “Electronics” Code = “naics:443112”

• extension element : Action– Annotated with a functional ontology concept.

• action = “Rosetta:RequestQuote”

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Annotating message types - simplecorrespondences

<wsdl:types> (...)

<xs:element name= "processPurchaseOrderResponse"type="xs:string (...)</wsdl:types>

Billing

AccountOrderConfirmation

xsd:string

OWL ontology

has_account

has_accountID

WSDL message element

1:1 Correspondences<xs:element name= "processPurchaseOrderResponse"

type="xs:stringwssem:modelReference="POOntology#OrderConfirmation"/>

results_in

semantic match

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Annotating message types - complexcorrespondences

<wsdl:types> (...) <complexType name=“Address"> <sequence> <element name=“StreetAd1“ type="xsd:string"/> <element name=“StreetAd2" type="xsd:string"/> ........... </sequence> </complexType> (...)</wsdl:types>

Address

StreetAddress

xsd:string

xsd:string

OWL ontology

hasCity

hasStreetAddress

hasZip

WSDL complex type element

1. modelReference to establish a semanticassociation

2. schemaMapping to resolve structuralheterogeneities beyond a semantic match

semantic match

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Using modelReference andschemaMapping

<complexType name="POAddress“wssem:modelReference="POOntology#Address”wssem:schemaMapping=”http://www.ibm.com/schemaMapping/POAddress.xq#input-doc=doc(“POAddress.xml”)”>

<all><element name="streetAddr1" type="string" /><element name="streetAdd2" type="string" /><element name="poBox" type="string" /><element name="city" type="string" /><element name="zipCode" type="string" /><element name="state" type="string" /><element name="country" type="string" /><element name="recipientInstName" type="string" /> </all></complexType>

Address

xsd:string

xsd:string

xsd:string

OWL ontology

has_City

has_StreetAddress

has_Zip


• modelReference at the complex type level– Typically used when specifying complex associations at leaf level is not possible– Allows for specification of a mapping function

semantic match

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• modelReference at the leaf levels– assumes a 1:1 correspondence between leaf elements and domain model

concepts

<complexType name="POItem" >

<all>

<element name="dueDate" nillable="true" type="dateTime" wssem:modelReference=”POOntology#DueDate”/> <element name="qty" type="float" wssem:modelReference=”#POOntology#Quantity”/> <element name="EANCode" nillable="true" type="string" wssem:modelReference=”POOntology#ItemCode”/> <element name="itemDesc" nillable="true" type="string" wssem:modelReference=”POOntology#ItemDesc” />

</all>

</complexType>

Item

dueDate

ItemDesc

Quantity

OWL ontology

hasIemDesc

hasDueDate

hasQuantity


Using modelReference andschemaMapping

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Representing mappings <complexType name="POAddress"wssem:schemaMapping=”http://www.ibm.com/schemaMapping/POAddress.xsl#input-doc=doc(“POAddress.xml”)”>

<all><element name="streetAddr1" type="string" /><element name="streetAdd2" type="string" /><element name="poBox" type="string" /><element name="city" type="string" /><element name="zipCode" type="string" /><element name="state" type="string" /><element name="country" type="string" /><element name="recipientInstName" type="string" /></all></complexType>

Address

xsd:string

xsd:string

xsd:string

OWL ontology

has_City

has_StreetAddress

has_Zip


....<xsl:template match="/">

<POOntology:Address rdf:ID="Address1">

<POOntology:has_StreetAddress rdf:datatype="xs:string">

<xsl:value-of select="concat(POAddress/streetAddr1,POAddress/streetAddr2)"/>

</POOntology:has_StreetAddress >

<POOntology:has_City rdf:datatype="xs:string">

<xsl:value-of select="POAddress/city"/>

</POOntology:has_City>

<POOntology:has_State rdf:datatype="xs:string">

<xsl:value-of select="POAddress/state"/>

</POOntology:has_State>....

Mapping using XSLT

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WSDL-S in perspective

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WSDL-S evolution

ActionAttribute forFunctionalAnnotation

Pre and PostConditions

Can useXML, OWL

or UMLtypes

Extension

Adaptation

schemaMapping

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...<xs:complexType name="processPurchaseOrderRequest"><xs:element name="billingInfo" type="xsd1:POBilling"/><xs:element name="orderItem" type="xsd1:POItem"/></xs:complexType></xs:schema><operation name="processPurchaseOrder” pattern=wsdl:in-out><input messageLabel = ”processPurchaseOrderRequest"element="tns:processPurchaseOrderRequest"/><output messageLabel ="processPurchaseOrderResponse"element="processPurchaseOrderResponse"/>...

WSDL

...<xs:complexType name="processPurchaseOrderRequest“wssem:modelReference="POOntology#OrderDetails” ><xs:element name="billingInfo" type="xsd1:POBilling"/><xs:element name="orderItem" type="xsd1:POItem"/></xs:complexType></xs:schema><operation name="processPurchaseOrder” pattern=wsdl:in-out><input messageLabel = ”processPurchaseOrderRequest"element="tns:processPurchaseOrderRequest"/><output messageLabel ="processPurchaseOrderResponse"element="processPurchaseOrderResponse"/>...

WSDL - SAnnotating aservice

UDDI

Semantic Layer

Publishing a service

WSDL-S in the life cycle of a Webservice


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WSDL-S in the life cycle of a Webprocess

Web Service Discovery

<Operation>

<Input2>

<Output2>

Service 2 Template

An abstract Web process

WSDL-SWSDL-S

<Operation>

<Output1>

Service 1 Template

<Input1>

<Operation>

<Output1>

Web service 1

<Input1>

<Operation>

<Output2>

Web service 2

<Input2>

WSDL-SmodelReferenceschemaMapping

Transformation

WSDL-SmodelReferenceschemaMapping

Process execution


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WSDL-S in action• ProPreO - Experimental Proteomics

Process Ontology (CCRC / LSDIS)

data

sequence

peptide_sequence

Excerpt: ProPreO – process ontology

<?xml version="1.0" encoding="UTF-8"?><wsdl:definitions targetNamespace="urn:ngp" ……xmlns:wssem="http://www.ibm.com/xmlns/WebServices/WSSemantics"xmlns:ProPreO="http://lsdis.cs.uga.edu/ontologies/ProPreO.owl" > <wsdl:types> <schema targetNamespace="urn:ngp" xmlns="http://www.w3.org/2001/XMLSchema"> ……</schema> </wsdl:types> <wsdl:message name="replaceCharacterRequest" wssem:modelReference="ProPreO#peptide_sequence"> <wsdl:part name="in0" type="soapenc:string"/> <wsdl:part name="in1" type="soapenc:string"/> <wsdl:part name="in2" type="soapenc:string"/> </wsdl:message>......

Excerpt: Bio-informatics Web service WSDLS

CCRC – Complex Carbohydrate Research Center www.ccrc.uga.eduProPreO - http://lsdis.cs.uga.edu/projects/glycomics/propreo/

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WSDL-S collaborations

• Meteor-S collaboration with WSMO– Using WSDL-S for grounding Web services

annotated with WSML ontologies

• Influencing OASIS / W3C

Requestor’s goal Service capability

WSDL-S

WSML WSML

Kunal Verma, Adrian Mochan, Michal Zaremba, Amit Sheth, John Miller, Christoph Bussler, Linking Semantics Web service Efforts - IntegratingWSMX and METEOR-S, Second International Workshop on Semantic and Dynamic Web Processes, July 2005

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WSDL-S annotator - Radiant

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Why WSDL-S ?• Approach simple, light-weight, upwardly

compatible with the existing WSDL standard– practical for adoption

• Approach agnostic to semantic representationlanguage– reuse of domain models– flexibility in choice of modeling language– annotation with multiple ontologies

• Ease in tool upgrades– e.g. wsif / axis invocation

More on METEOR-S Web site

Web Service Semantics - WSDL- S · 3 Adding semantics to WSDL – guiding principles •Build on existing Web Services standards •Mechanism independent of the semantic representation

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